1. Technical Field
The present disclosure relates to acoustic devices, particularly, to a thermoacoustic device.
2. Description of Related Art
In a paper entitled “Flexible, Stretchable, Transparent Carbon Nanotube Thin Film Loudspeakers” by Jiang et al., Nano Letters, Oct. 29, 2008, Vol. 8 (12), 4539-4545, a loudspeaker is proposed. The loudspeaker adopts a carbon nanotube thin film as a sound emitter. Sound waves based on the thermoacoustic effect are generated by inputting an alternating current to sound emitter. The carbon nanotube thin film has a smaller heat capacity and a thinner thickness, so that it can transmit heat to surrounding medium rapidly. When the alternating current passes through the carbon nanotube thin film, oscillating temperature waves are produced in the carbon nanotube thin film. Heat waves excited by the alternating current are transmitted to the surrounding medium, causing thermal expansions and contractions of the surrounding medium, thus producing sound waves.
When the sound waves are generated by the carbon nanotube thin film, the carbon nanotube thin film projects heat waves in all directions. Consequently, other parts in the loudspeaker besides the sound emitter will absorb heat, and a temperature of the entire loudspeaker is elevated, lowering a capability of the loudspeaker.
What is needed, therefore, is to provide a thermoacoustic device having a lower temperature.